Quantitative counterimmunoelectrophoresis assay for prostatic acid phosphatase.

We developed two quantitative counterimmunoelectrophoretic (CIEP) assays to detect serum prostatic acid phosphatase (PAP). The assays were designated counterimmunoelectrophoresis-colorimetric (CIE-C) and counterimmunoelectrophoresis-densitometric (CIE-D). One unique feature of these assays was the use of a primary standard for the quantitation of PAP. The sensitivities of the assays were 0.08 and 0.04 IU per liter for CIE-C and CIE-D, respectively. Precision coefficients of variation and recovery studies for four levels of PAP over a 3-month period have shown the reliability of these newly modified assays. PAP activity in sera from patients with early stages of prostatic cancer which was demonstrated to be normal by conventional chemical methods was found to be elevated by the conbined methods in a substantial number.